Integrated: 8373134: C2: Min/Max users of Min/Max uses should be enqueued for GVN

[Galder Zamarreño]

On Thu, 18 Dec 2025 11:31:30 GMT, Galder Zamarreño <galder at openjdk.org> wrote:

> Min/Max users of Min/Max uses need to be enqueued respectively to the GVN worklist to see if further optimizations can be applied. Without this, there are cases where additional potential ideal/identity optimizations are not applied. I need this fix to test min/max reassociation implementation with IR tests reliably.
> 
> Aside from the fix itself, I've refactored `MaxNode` to `MinMaxNode` and added a `is_MinMax` node query to simplify the fix.
> 
> I have also removed the Min/Max exceptions in `PhaseIterGVN::verify_Identity_for` since this fix fixes `compiler/codegen/TestBooleanVect.java` with `-XX:VerifyIterativeGVN=1110`.
> 
> To test this I've created a template framework test that validates the fix. I have tested with all Min/Max combinations including Float16, which I've verified with Intel SDE. Float16 does not use `Argument.NUMBER_42` because there's no support for it yet, see [JDK-8373977](https://bugs.openjdk.org/browse/JDK-8373977).
> 
> During development I noticed that the test only failed when the test had `b, a` parameters in that order, so I added tests for both cases as `a, b` and `b, a` so that all possible orders are covered and they don't slip in the future.
> 
> I've run tier1-3 tests on linux/x64 successfully.

This pull request has now been integrated.

Changeset: d16a9b2e
Author:    Galder Zamarreño <galder at openjdk.org>
Committer: Emanuel Peter <epeter at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/d16a9b2ec507251a44f034f1ccf8039f02023d52
Stats:     251 lines in 9 files changed: 200 ins; 0 del; 51 mod

8373134: C2: Min/Max users of Min/Max uses should be enqueued for GVN

Reviewed-by: epeter, bmaillard, dlong

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PR: https://git.openjdk.org/jdk/pull/28895